No dealer should be accepting/taking deposits for a car that doesn't exist.
But you should be able to register your interest with a dealer.
I have told my dealer I will buy one and I want to order as soon as the order book opens.
When this happens and the order is confirmed they will contact me and I will pay a deposit then. This is the way it should be and no money should change hands until the car is "officially" available fom Ford.
Quite a few dealers faced legal action from Focus RS owners over the way the whole deposit/order situation was handled.
One dealer even took a "full" deposit of well over £20k from one customer, then when the price was announced at £20k refused to return the difference until the car was delivered. The customer took legal action.
The same applies with the Fiesta RS Concept. It is still officially just that a concept and no dealer should be taking deposits on them.
Mike